The 21-year-old ignored offers from Beşiktaş, Galatasaray and Sevilla to join the German League side in 2016, and he has since then been impressive for the club.
The club's head of recruitment Sven Mislintat has free rein to push through these deals as a replacement for Arsene Wenger has not been found.
Club captain Per Mertesacker will now retire from his playing duties and assume a new role as manager of Arsenal's academy, whilst fellow centre back Laurent Koscielny has been ruled out until December with his Achilles injury.
Bundesliga outfit Freiburg will not be prepared to let their man leave for a bargain price however.
On the pitch, it was another disappointing season for the Gunners, who finished in sixth place in the Premier League standings, meaning that they will be without Champions League football for the second term running.
Soyuncu has been likened to Bayern Munich defender Mats Hummels due to his possession style of football, and it is also believed that he will thrive should he decide to join the Gunners.
Although the youngster is interesting other Premier League clubs, they "have been told in recent days that he is destined to join Arsenal".
"For me it is like a puzzle - first the instructions are quite abstract, but in the end everything gets a practical dimension".
It looks very possible that this transfer will be the first signing of the summer for Arsenal, who desperately need to bolster their defence after a very shaky season.